Currently, in the field of injection molds and particularly, in injection molds for obtaining molded plastic parts which have negatives and which, therefore, cannot be demolded by conventional demolding systems, the use of angular shifting mechanisms associated with the mold is required, such that the demolding of these negatives is facilitated without complicating the molding cycle as a result. Mechanisms of this type, described for example in patent application ES-A-2219196, comprise an ejector shaft with a first end portion attached to a mobile ejector plate which shifts in an axial plane, and a second end portion coupled by means of a coupling element to a slide comprising a molding portion provided with a geometry of at least one negative of a molded part and a push surface which are in contact with the molded part during molding, as well as a radially inclined segment with respect to said axial plane.
This mechanism further comprises a fixed sliding support with a slope with a complementary inclination with respect to the inclination of the inclined segment of the slide and on which the inclined segment of the slide shifts, such that when the ejector shaft pushes the slide towards the part to be obtained, the slide shifts through the slope along an inclined shifting path, such that the molding portion is separated from the part to be obtained. The mechanisms require complex machining because it cannot be performed perpendicular and therefore requires complex mechanisms and adjustments that are hard to carry out.
In mechanisms of this type it is very important to pay special attention to the tolerances of all the components comprising the set of this portion of the mold because any variation on the height of these elements distorts the adjustment of the system, greatly complicating its operation. Depending on the height of the mold, the distance separating the runners located in the ejector plates of the mold to the slide through the inclined guide causes a separation which forces a very high force for extracting the plastic part, which requires oversizing the ejector plates for the purpose of withstanding the force required for shifting the slide from the ejector plates themselves.
Spanish invention patent application ES-A-2220158 describes a mechanism for the molding and the expulsion of negatives in injection molds with a relatively simplified construction with respect to other previously existing mechanisms, which allows reducing manufacturing costs and times. Although this mechanism is advantageous, it has a constructive configuration which is essentially intended for a part with a specific design with its respective negatives, which involves the need for a specific construction for each type of part. Furthermore, on some occasions due to the shape of the part, it is necessary for the constructive configuration to be more complex in order to extract the part because it cannot be vertically extracted and on some occasions it increases the complexity to the point in which the shaft associated with the ejector plate works at an angle of inclination with respect to the vertical ejection shaft for ejecting the part.
Based on the foregoing, there is a need to find an improved constructive solution which provides greater versatility.